fixes stated grammar for block comments, by adding Kleene '+' in two places.

Closes #1588
fix another subtle bug in comment regex
added defn of non_slash_or_star
testsuite: Add test case for #4325
core: Inline mallocing wrapper functions

As far as I can tell, this doesn't make rust compile any
faster, but it does at least remove one level of indirection
on malloc, which might help speed up some operations.
std: change Decoder::read_option to return a generic type

This allows read_option to be used with a custom option type instead
of just core::Option.
Fix warning about unused imports in import lists

Before, if anything in a list was used, the entire list was considered to be
used. This corrects this and also warns on a span of the actual unused import
instead of the entire list.
Removing unused imports
libcore: language change minor fix for ARM & MIPS
auto merge of #5620 : catamorphism/rust/issue-4325, r=catamorphism
auto merge of #5622 : yichoi/rust/pull-0329, r=catamorphism

libcore: language change minor fix for ARM & MIPS

fix context.rs
auto merge of #5570 : alexcrichton/rust/fix-unused-imports, r=sanxiyn

Before it wouldn't warn about unused imports in the list if something in the list was used. These commits fix that case, add a test, and remove all unused imports in lists of imports throughout the compiler.
std: remove prettyprint

Everyone uses fmt!("%?", ...) instead of the prettyprint
module, so I'm removing this file.
core: add LinearMap::with_capacity
std: remove Encoder::emit_{owned,managed}_str and Decoder::read_{owned,managed}_str
std: remove Encoder::emit_{owned,managed} and Decoder::read_{owned,managed}
std: remove Encoder::emit_{owned,managed}_vec and Decoder::read_{owned,managed}_vec
std: remove Encoder::emit_tup{,_elt} and Decoder::read_tup{,_elt}
std: remove Encoder::read_rec and Decoder::emit_rec
core: add consume_reverse